Section 4. Walbro Carburetors; Hh80 - 120, Vh80 - 100 - Tecumseh HH100 Handbook

WALBRO CARBURETORS. Following are initial
carburetor adjustments to be used to start the engine.
After the engine has reached operating temperature,
make final adjustments.
Main Adjustment HH80, 100, 120
Screw VH80, 100, 1-1/2 turns off seat
Idle Adjustment HH80, 100 120
Screw VH80 100 1-1/4 turns off seat
For proper carburetion the atmospheric vent MUST
be open. Examine and clean if necessary.
A sluggish engine speed control may at times be
caused by dirt or paint on the throttle return spring.
Clean if required.
Choke lever positioning is maintained by the stop
spring, replace if damaged.
The fuel inlet fitting should be checked if leakage
is detected in the carburetor area. Do not screw in
too tight, this may crack the carburetor body. The
fuel bowl drain should also be examined in event
fuel leakage is detected. It may be necessary at
times to replace the internal rubber seat. Examine
the throttle return spring if slow engine response is
noted during operation. Correct by cleaning the throttle
return or realigning the throttle plate.
CHOKE STOP SPRING
CHOKE LEVER
FUEL INLET
FUEL BOWL
10

SECTION 4. WALBRO CARBURETORS

HH80 - 120, VH80 - 100

THROTTLE LEVER
THROTTLE RETURN
SPRING
SECONDARY
IDLE DISCHARGE
PRIMARY IDLE
DISCHARGE
THROTTLE SHUTTER
FUEL BOWL NUT
HIGH SPEED
ADJUSTMENT SCREW
Install the throttle plate with the numbers (if present)
facing out when closed. Move the throttle shaft to
the closed position, place the throttle plate on the
shaft and secure with the retaining screws. The throttle
should move freely. If binding is present, correct by
loosening screws and repositioning throttle plate.
THROTTLE SHUTTER
MOUNTING
FLANGE
Examine the inlet needle. "A" is a needle that is
serviceable, if the tip appears damaged as "B", replace
needle and seat assembly. Tighten the inlet seat to
40 to 50 inch pounds (4.5 - 5.7 Nm). Always use a
new gasket. Clean all dirt from the inlet seat cavity.
Normally the main nozzle should not be removed.
It is possible to clean the carburetor with solvent
and compressed air. Remove and replace the main
nozzle only if the high speed needle seat is damaged
or because of excessive dirt.
"B" DAMAGED
- Replace
INLET
NEEDLE
"A"
INLET
SEAT
INLET SEAT
INLET SEAT
CAVITY
GASKET
THROTTLE LEVER
THROTTLE STOP
SCREW
INSTALL WITH
NUMBERS OUT
62
29
MAIN NOZZLE
EMULSION TUBE